Solution:Preferential trade Agreements by the countries to give preference to access certain products from participating countries.
2. Frees-Trade Arco- Remove barriers trade among members but each country has own policies for nonmembers.
3. Custom Union - Remove barriers to trade among members, and set a common trade policy against nonmembers.
4. Common Market - Remove barriers to trade labour & capital among members and set a common trade policy against nonmembers.
5. Economic Union - Remove barriers to trade, labour, & capital among members and set a common trade policy against nonmembers and coordinate members economic policies.